Soldered heat exchanger

ABSTRACT

The invention relates to a soldered heat exchanger, especially a capacitor for a motor vehicle ventilation system, comprising a heat exchanger network made of tubes and ribs and at least one collector pipe made of a base ( 2 ) and a cover ( 3 ) and separating walls ( 8 ), whereby the base ( 2 ) and the cover ( 3 ) have edges ( 4, 5, 6, 7 ) which overlap on the longitudinal sides thereof. The base ( 2 ) receives the ends of the tubes and the separating walls ( 8 ) are fixed in relation to the cover ( 3 ) by means of a first and second shoulder ( 8   b   , 8   c  and a lug ( 8   a ). According to the invention, groove-shaped recesses ( 3   b   , 3   c ) are arranged in the edges ( 6, 7 ) of the cover ( 3 ) in the region of the separating walls ( 8 ), wherein the shoulders ( 8   b   , 8   c ) of the separating walls ( 8 ) engage. A secure positioning of the separating walls in the collector pipe is obtained in addition to a leakage-free soldering of the capacitor.

The invention relates to a soldered heat exchanger, in particular asoldered condenser for a motor vehicle air conditioning system,according to the preamble of patent claims 1 and 2, known from DE-A 4339 952.

The known heat exchanger is what is known as a flat tube condenser whichconsists of flat tubes, of corrugated ribs arranged between these and oftwo-part headers with partitions. All the parts, which consist of analuminum alloy, are first joined mechanically and then soldered in asoldering furnace. The partitions are inserted as separate individualparts into the headers and are positioned there. The headers consist ofa dish-shaped bottom which receives the tubes and of a likewisedish-shaped cover which has slots for receiving and positioning thepartitions. When these three parts, that is to say the bottom, thepartitions and the cover, are being joined together, tolerance problemsmay arise, because the partitions, on account of their geometric design,bear against the bottom at one point, but against the cover at twopoints, and this may lead to a static overdetermination of these threeparts and consequently to leaks after the soldering process.

The object of the present invention is to improve a positioning andfastening of the partitions in the header of the condenser initiallymentioned, to the effect that a correct positioning of the partition inthe header and leakage-free soldering are ensured.

This object is achieved, for the heat exchanger initially mentioned, bymeans of the features of patent claims 1 and 2. Accordingly, the coverof the header has at its edges, in the region of the partitions, cutoutsinto which the partitions engage, that is to say each partition formswith the cover a joining connection at two points (claim 1) or at threepoints (claim 2): by means of the twofold joining connection accordingto claim 1 between the steps of the partition and the cutouts in thecover, the partition is already fixed sufficiently, and a tap, as it maybe referred to, such as is present in the prior art, may be dispensedwith. In the alternative solution according to claim 2, the partitionhas, as is known, a tab which is introduced into the corresponding slotof the cover. The steps of the partition insert themselves into the edgecutouts of the cover, so that a “three-point mounting” for the partitionis afforded after the joining operation. The partition can therefore nolonger tilt, but is oriented exactly, that is to say at an angle of 90°,to the longitudinal axis. The dimensions of the partition and of theedge cutouts in the cover are selected such that the partition restsinside the cover, but not with its steps in the cutouts. After thepartitions and the cover have been joined together, the bottom is pushedover the cover, together with the premounted partitions, into abutmentagainst the partitions and, as is known, is secured by means of punchblows. The bottom therefore then bears with its inner face against thepartition at only one point. This results, overall, in a staticallydeterminate system of cover, partition and bottom, that is to say thereare unequivocal bearing faces with minimal gaps, so that leakage-freesoldering can be achieved.

In a further refinement of the invention, some play is provided betweenthe steps of the partition and the base surface of the edge cutouts.This ensures that there is only one bearing face in each case betweenthe partition, on the one hand, and the cover and bottom, on the otherhand. The gap defined by tolerance is filled with solder material duringthe soldering process and thus results in leaktight soldering.

Exemplary embodiments of the invention are illustrated in the drawingand are described in more detail below. In the drawings:

FIG. 1 shows a cross section through a header with a partition,

FIG. 1 a shows a side view of FIG. 2,

FIG. 2 shows a cross section through the cover and the partition of theheader,

FIG. 2 a shows a side view of FIG. 2,

FIG. 3 shows a cross section through the cover of the header in theplane of the partition,

FIG. 3 a shows a side view of FIG. 3 and

FIG. 4, 4 a show a modified embodiment with a partition without “tab”.

FIG. 1 shows a cross section through a header 1, the cross section ofwhich is delimited by a dish-shaped semicylindrical bottom 2 and alikewise dish-shaped semicylindrical cover 3 which is configured interms of its outer dimension in such a way that it can be inserted intothe bottom 2. The bottom 2 has two edge regions 4, 5 which run in thelongitudinal direction of the tube (perpendicularly to the drawingplane) and which overlap with edge regions 6, 7 of the cover 3. Thecross section of the header 1, thus formed by the bottom 2 and the cover3, is filled with a partition 8 which, in its region facing the cover 3,has a tab 8 a which passes outward through a recess 3 a (cf. FIG. 3) ofthe cover 3. Furthermore, the partition 8 has two steps 8 b, 8 c in theregion of the edges 6, 7 of the cover 3. The bottom 2 receives, in a waynot illustrated in any more detail (for example, in rim holes), flattubes 9 which, together with corrugated ribs, not illustrated, form thenetwork of a condenser for a motor vehicle air conditioning system.

FIG. 2 and FIG. 2 a show the header 1 without the cover 2, that is tosay only with the bottom 3 and the partition 8 which has a width b.

FIG. 3 and FIG. 3 a show the cover 3 as an individual part, and, on theone hand, the slot 3 a for receiving the tabs 8 a, not illustrated here,and, on the other hand, the two cutouts 3 b, 3 c in the edges 6, 7 ofthe bottom 3 can be seen here. The cutouts 3 b, 3 c have a U-shapeddesign, that is to say are open outward, and have two parallel sidefaces 13, 14 and a base surface 15 running perpendicularly to these. Thedistance between the two side faces 13, 14 has the dimension b whichcorresponds to the width b of the partition 8.

The assembly of the header 1 is carried out as follows: first, thepartitions 8 are inserted into the cover 3, specifically firstintroduced with their tab 8 a into the slots 3 a. After a shortintroduction travel, the steps 8 b, 8 c engage into the groove-shapedincisions 3 b, 3 c, that is to say the partition portions 8 b, 8 c slidein the manner of a feather key into a groove. The introduction movementof the partition 8 is terminated when the abutment point A1 inside thecover is reached. In this position, there is still some air, that is tosay a minimal gap s (cf. FIGS. 1 a and 2), located between the steps 8b, 8 c and the base surface 15 of the incisions 3 b, 3 c. This ensuresthat the partition 8 is always moved up to the abutment A1. Owing to thetolerances between the partition 8, 8 a and the slot 3 a and also theincisions 3 c, 3 b, the partition 8 is clamped slightly in thisposition, so that it is fixed. The bottom 2 is thereafter pushed ontothe cover 3 (or the cover 3 together with the partition 8 is pushed intothe bottom 2). This pushing-in movement takes place until the partition8 touches the abutment point A2 inside the cover 2. This ensures thatthe partition 8 has only one abutment point, to be precise A2, with thebottom 2. The result of this is that the partition 8 can come to bearover the full circumference both with respect to the inner wall of thecover 2 and with respect to the inner wall of the bottom 3. Furthermore,by means of the three-point mounting already mentioned above, thepartition 8 is also oriented perpendicularly to the longitudinal axis,that is to say the circumferential surface of the partition 8 runsparallel to the inner wall of the cover 3 and bottom 2. These are thepreconditions for satisfactory soldering. The gap s existing between thesteps 8 b, 8 c and the base line 15 of the incisions 3 b, 3 c is filledwith solder during the soldering process and, moreover, is coveredoutwardly by the overlapping edge regions 4, 5 of the bottom, so thatthere is leaktightness both outwardly and between the two adjacentchambers 10 and 11.

After the partitions 8, cover 3 and bottom 2 have been joined together,the edge regions 4/6 and 5/7 overlapping one another may be secured bymeans of punch blows, as is known from the prior art initiallymentioned. The entire condenser is thereafter soldered in the furnace.

FIGS. 4 and 4 a show a further exemplary embodiment of the inventionwith a modified partition form in an illustration similar to FIGS. 2 and2 a. FIG. 4 shows, in a cross section, a cover 20 of a header, not fullyillustrated. The cover 20 has an approximately semioval cross sectionand is delimited upwardly (in the drawing) by edge regions 21, 22. Inthese edge regions 21, 22 are arranged, in each case at the points wherea partition is provided, groove-like incisions 24, 25 which areillustrated by broken lines in FIG. 4, only the front incision 24appearing in FIG. 4 a. The free cross section of the cover 20 hasinserted into it a partition 23 which with its lower half 23 a bearsover its entire circumference against the inner face of the cover 20.The upper half 23 b of the partition 23 has a diameter Db larger bydouble the wall thickness d than the lower half 23 a having a diameterDa. The two cross-sectional halves 23 a and 23 b merge one into theother in each case via a step 23 c, 23 d. The steps 23 c, 23 d engageinto the incisions 24, 25 and thus form a twofold joining connectionbetween the partition 23 and cover 20; this is sufficient forpositioning the partition 23. In contrast to the previous exemplaryembodiment, illustrated in FIGS. 1 to 3, the partition 23 has no tabinserted through a slot in the cover. Instead, the cover 20 has acontinuous cross section, that is to say a cross section not interruptedby slots. Consequently, the insertion of the partition through the coverand subsequent soldering are dispensed with, that is to say the risk ofa leakage is further reduced.

The partition 23 is mounted by being inserted with its smaller half 23 ainto the cover 20 a, so that the partition 23 forms with cover 20 acommon abutment face B1. So that abutment or contact occurs definitivelyin the region B1, a gap s is left between the edge regions 21, 22 andthe steps 23 c, 23 d. The steps 23 c, 23 d thus insert themselves intothe groove-like cutouts 24, 25 of the cover 20 in the manner of afeather key/groove connection.

To complete the header, a bottom, not illustrated here, is pushed overthe cover 20, with the partition 23 inserted, in similar way to theexemplary embodiment according to FIG. 1, so that an abutment face B2 isformed between the partition 23 and the bottom, not illustrated. Thisresults, for mounting the entire header consisting of the cover 20,partition 23 and bottom, not illustrated, because of only two abutmentfaces B1, B2, in defined abutment conditions, that is to say aleakage-free soldering of the partition 23 in the header.

1. A soldered heat exchanger, in particular a refrigerant condenser,comprising a heat exchanger network consisting of tubes and ribs andcomprising at least one header which consists of a bottom and a coverand of partitions, the bottom and cover having edges overlapping oneanother along the sides, the bottom receiving the edges of the tubes,and the partitions having a first and a second step which rests on theedges of the cover, wherein the two edges of the cover have, in theregion of the partitions, groove-like recesses, into which the steps ofthe partitions engage; wherein after the bottom and cover have beenjoined together, the partitions in each case form a first bearing facewith the cover and a second bearing face with the bottom, while a gap isleft between the steps of the partitions and the base surface of therecess.
 2. The heat exchanger as claimed in claim 1, wherein therecesses have two parallel side faces and a base surface arrangedperpendicularly to these, and in that the distance between the sidefaces corresponds to the width of the partition.
 3. A soldered heatexchanger, in particular a refrigerant condenser, comprising a heatexchanger network consisting of tubes and ribs and comprising at leastone header which consists of a bottom and a cover and of partitions, thebottom and cover having edges overlapping one another along the sides,the bottom receiving the ends of the tubes, and the partitions having ineach case a tab, which passes through a slot in the cover, and a firstand a second step which rests on the edges of the cover, wherein the twoedges of the cover have, in the region of the partitions, groove-likerecesses, into which the steps of the partitions engage; wherein afterthe bottom and cover have been joined together, the partitions in eachcase form a first bearing face with the cover and a second bearing facewith the bottom, while a gap is left between the steps of the partitionsand the base surface of the recess.
 4. The heat exchanger as claimed inclaim 2, wherein the recesses have two parallel side faces and a basesurface arranged perpendicularly to these, and in that the distancebetween the side faces corresponds to the width of the partition.